As flash memory technology becomes more advanced, flash memory is replacing traditional magnetic disks as storage media for mobile systems. Flash memory has significant advantages over floppy disks or magnetic hard disks such as having high-G resistance and low power dissipation. Because of the smaller physical size of flash memory, they are also more conducive to mobile systems. Accordingly, the flash memory trend has been growing because of its compatibility with mobile systems and low-power feature. However, advances in flash technology have created a greater variety of flash memory device types that vary for reasons of performance, cost and capacity.
A conventional method of manufacturing micro flash memory cards is to use either pre-molded one sided or two sided package with large enough cavity to hold the rectangular micro flash memory card block by gluing to the package's cavity. The package can fall apart as the adhesive quality degraded.
The conventional method has a limitation as assembly packaged memory and controller chips have larger dimension than the bare die plus the pads of COB (chip-on-board). Other disadvantages of the conventional method are: 1) the package has limited Z-height to stack chips to increase memory capacity; 2) there are more process variables to cause open and short defect that causes lower yield; 3) water and moisture can penetrate the shell package to corrode the leads of the components and cause reliability problem and shorten the useful life time of the device; and 4) the shell package internal cavity has to conform to the changing contour of the components on PCBA (printed circuit board assembly).